Circuits of lower-cost, more reliable, faster and higher-density are the goal pursued by integrated circuit packaging. In the future, integrated circuit packaging will increase the integration density of various electronic components by continuously reducing the minimum feature size. At present, advanced packaging methods include Wafer Level Chip Scale Packaging (WLCSP), Fan-Out Wafer Level Packaging (FOWLP), Flip Chip (Flip Chip), Package on Package (POP), and so on.
Fan-out wafer level packaging is an embedded chip packaging method based on wafer level processing, and it is one of the advanced packaging methods with more input/output (I/O) ports and better integration flexibility. Fan-out wafer level packaging has the following unique advantages over conventional wafer level packaging: 1) I/O spacing are flexible and it is independent of chip sizes; 2) only effective dies are used and the product yield can be improved; 3) the 3D packaging path is flexible and patterns in any array can be formed at the top; 4) the electrical and thermal performance is better; 5) it can be applied in high frequencies; and 6) it is easy to achieve high-density wiring in a redistribution layer (RDL).
At present, a fan-out wafer level packaging method of radio frequency chips generally comprises the following steps: providing a carrier and forming an adhesive layer on a surface of the carrier; obtaining a redistribution layer (RDL) on the adhesive layer by performing photo-etching and electroplating; mounting the radio frequency chip on the redistribution layer by adopting a chip bonding process; packaging the chip in a plastic packaging material layer by adopting an injection molding process; removing the carrier and the adhesive layer; forming an Under-Bump Metal (UBM) layer on the redistribution layer by performing photo-etching and electroplating; performing ball placement and reflow on the UBM layer to form a solder ball bump; and then performing wafer bonding and dicing. For the sake of communication effect, antennas will be provided when the radio frequency chip is used, and for the existing radio frequency chip, antennas are directly laid out on a PCB or interfaces for connecting external antennas are provided by developers when layout design is performed for radio frequency function modules. However, due to the inconvenience in connecting the external antennas, most of the existing antennas are laid out directly on the PCB, in order to ensure the antenna gain, the size of the antennas must be large enough, and this will inevitably be at the expense of the PCB area, such that the area of the PCB and the entire packaging structure will become larger.
In view of this, it is necessary to design a new fan-out antenna packaging structure and a preparation method thereof to solve the above-mentioned technical problems.